Lipophilic Polycation Vehicles Display High Plasmid DNA Delivery to Multiple Cell Types

Area of Science:

• Biomaterials Science
• Gene Delivery Systems
• Polymer Chemistry

Background:

• Developing efficient and safe non-viral vectors for plasmid DNA (pDNA) delivery is crucial for gene therapy and genome editing.
• Cationic polymers offer potential as pDNA carriers, but their efficacy and safety profiles require optimization.

Purpose of the Study:

• To design and evaluate a novel class of cationic poly(alkylamidoamine)s (PAAAs) with varying lipophilicity as in vitro pDNA delivery agents.
• To systematically investigate the structure-activity-toxicity relationships of these PAAAs.

Main Methods:

• PAAAs were synthesized using step-growth polymerization with varying methylene linker lengths to control lipophilicity.
• pDNA complexation and polyplex formation were assessed in reduced serum medium.
• In vitro transgene expression (GFP) and cytotoxicity were evaluated in multiple human cell lines (HDFa, HeLa, HMEC, HUVEC).

Main Results:

• Synthesized PAAAs effectively complexed with pDNA, forming polyplexes around 1 μm in diameter.
• Select PAAA formulations demonstrated superior transgene expression compared to Lipofectamine 2000, with comparable or better cell viability.
• Transgene expression varied by cell type, peaking in HeLa cells (~90%) and lower in HDFa cells (up to ~20%).
• Cytotoxicity correlated positively with polymer molecular weight, N/P ratio, and methylene linker length.

Conclusions:

• PAAAs represent a promising new class of tunable non-viral vectors for pDNA delivery.
• The design strategy balances polycationic and lipid-like attributes, offering a scaffold for optimizing gene delivery vehicles.
• These PAAAs show potential for applications in genome editing and other gene therapy strategies.